With rapid development of electronic technology, a power density of a power device becomes higher and higher. When the power device is rapidly and frequently switched between turn-on and turn-off, yielded heat is also more and more. In order to assure the power device to work normally, it must dissipate heat in time and efficiently. Since if the heat yielded by the power device can not be dissipated in time and efficiently, a temperature of the power device will be raised, the effectiveness will be lowered and the service life will be reduced in an unserious case, it would result in failure of the power device or device explosion in a serious case. Therefore, the power device package factory and the user of the power device are always puzzled in the heat dissipation problem. High efficient heat dissipation technology is one of important respects always kept on research and development in the electronic industry.
At present, a power module with a large power (the power module is a module which is formed by combining power electronic devices in a certain function and then encapsulating them), such as a SVG (Static Var Generator), a MVD (Medium Voltage Drive), an UPS (Uninterruptible Power System), and a wind power converter, and so on, is mainly composed of an IGBT (insulated gate bipolar transistor) device. A conventional heat dissipation manner is to use an all-metal type heat sink. As shown in FIG. 1, a power device 10 is secured on one side of a heat sink base 20, and a heat dissipation fin group 30 composed of a plurality of heat dissipation fins is on the other side of the heat sink base 20, engagement of the heat sink base 20 and the heat dissipation fin group 30 employs an extrusion formed integral structure or an insert fin type structure or a welding fin structure. In order to make heat yielded by the power device 10 to be efficiently transferred to the heat dissipation fin group 30 and then dissipated to air, it is required that each of the power devices is reasonably arranged on the heat sink base 10 so as to make a temperature of the heat sink base 20 relatively uniform and promote the efficiency of the heat sink. However, as a result, a distance between the power devices is relatively large, electrical connection distance therebetween is increased, the leakage inductance is increased, and efficiency is relatively low, it has unfavourable effect on the performance and service life of the power devices, and more unfavourable especially for parallel topology of a plurality of the IGBTs. And for a power module with large power, since thermal flux of a single power device is large, the heat dissipation can not be solved in the conventional all-metal heat dissipation manner.